Many celebrities had an up-and-down year — especially when it came to their waistlines!

In our special year-end look back at 2012, ON YOUR RADAR, we’re taking a look back at some of Hollywood’s biggest “Winners” and “Sinners” when it came to their ever-changing bodies.

We begin with the “Sinners” and Christina Aguilera: The Beautiful singer flaunted a fuller figure throughout the year, culminating in an outing at November’s American Music Awards where her curves were on full display. “The challenge I’ve always had is being too thin,” Christina told Lucky magazine, “so I love that now I have a booty and obviously I love showing my cleavage.”

SINNERS

Demi Moore

The Striptease star, still licking her wounds after a painful breakup from Ashton Kutcher — and his subsequent romance with Mila Kunis — alarmed friends and loved ones, showing a gaunt figure at times throughout 2012.

Ali Lohan

Lindsay Lohan‘s younger sister, an aspiring model, cut such a slim figure, rumors of an eating disorder sprouted up in the media. One diet expert said of Ali: “It definitely seems like there is an eating disorder or super serious dieting going on, which she clearly doesn’t need — it is frightening.”

Erin Wasson

Some thought the statuesque Texas-born model bared too slim a figure this year. The 30-year-old has been seen on shows such as America’s Next Top Model and Project Runway.

Val Kilmer

The 90s heartthrob’s weight problems continued in 2012, as the one-time leading man of blockbusters like The Doors, Heat and Batman Forever looked worse for wear during a smattering of public appearances.

Matthew McConaughey

The Magic Mike star remains a man committed to his craft, wasting away to just 143 pounds for his role as AIDS patient Ron Woodruff in the upcoming film, The Dallas Buyers Club.

Lady Gaga

The Bad Romance singer gained an estimated 25 pounds in 2012, so much so that at one point her record label took notice. Gaga, who’s battled with eating disorders in the past, shot back, “This is who I am. And I am proud at any size.”

Fiona Apple

The Criminal crooner sparked speculation when she took the stage for an autumn concert in New Orleans looking emaciated.

Anne Hathaway

The 30-year-old Les Miserables beauty — who shed 25 pounds from an already-thin frame for the film — called her body an “ongoing source of shame,” noting, “I still feel the stress over ‘Am I thin enough? Am I too thin? Is my body the right shape?’ … There’s an obsessive quality to it that I thought I would’ve grown out of by now.”

Jennifer Connelly

The Reservation Road actress, and avid exercise buff, turned heads this past summer when she was snapped looking thin while on a jog. One expert told us, “It appears that she overtrains.”

Rosie Huntington-Whiteley

The British beauty’s slim figure came under scrutiny in 2012, as some experts said she carried too little weight for her frame. “It takes lots and lots of hard work. I have three personal trainers — James Duigan in London, Jason Walsh in Los Angeles and my friend Justin in New York,” she told Grazia magazine. “That means there’s no excuse not to be in the gym wherever I go.”

Candice Swanepoel

The Victoria’s Secret Angel, a native of South Africa, raised eyebrows when she sent a tweet putting her concave stomach and jutting hipbones on display. She later shot back, “I am healthy and happy. I’m heartened to know how much everyone cares about me, but in this case, everything is normal and good.”

WINNERS

And now, the “Winners,” starting with Jessica Simpson …

Jessica Simpson

The Fashion Star leading lady lived up to her Weight Watchers contract, having lost 60 pounds after giving birth to her daughter Maxwell in May. She’ll stay aboard with the company through her newly-announced second pregnancy.

Snooki

Jersey Shore‘s breakout star didn’t need much time to shed her baby weight following the August 26 birth of her son, Lorenzo Dominic LaValle.

LeAnn Rimes

The former child star vented after pundits suggested a possible eating disorder to explain sudden weight loss. She told Chelsea Handler, “I was a baby! I was fat. I had baby fat. I grew up. I work out. There’s nothing else to explain.”

Nicole Richie

The Simple Life star has displayed a much healthier frame since her rail-thin figure of yesteryear. She said, “I feel great about my body. You know, aesthetically I can be picky, but I choose not to. I’ve taken huge leaps. I’m proud of that.”

Jennifer Hudson

The Dreamgirls beauty continued to maintain her svelte frame after losing more than 80 pounds in 2010 following the 2009 birth of her son, David Jr. “I’m at the weight I want to be,” she told Redbook. “But I hear all the time, ‘Don’t lose any more weight, you need to stop.’ People are under the impression that I’m still losing but I’m not.”

Mariah Carey

The All I Want For Christmas singer continued to maintain a curvy frame this past year after the 2011 birth of her twins Monroe and Moroccan. She’ll be plenty busy in 2013 as one of the judges on American Idol.

Kristen Cavallari

The Hills beauty, 25, quickly got back into form after having her son with Chicago Bears quarterback Jay Cutler, Camden Jack, on August 8.

Beyonce

The Single Ladies superstar lost 60 pounds after the January birth of her daughter Blue Ivy. She told concertgoers in May, “Y’all have no idea how hard I worked. I had to lose 60 pounds. They had me on that treadmill. I ate lettuce!”

Alessandra Ambrosio

The Victoria’s Secret supermodel wasted little time shedding the excess pounds following the birth of her son Noah, as the Brazilian beauty looked like she’d lost most of the weight just a month after having the boy in May.

Hilary Duff

After giving birth to son Luca in March, the ex-Disney actress gradually got her figure back. She said, “Everyone wants their body back, but all in time. It took nine months to get there and so hopefully, it won’t take that long to get it off, but I’m doing it slowly.”

Jordin Sparks

American Idol‘s sixth season winner lost 50 pounds and four dress sizes in 2012, “I just wanted to be healthy,” she told Shape, outlining the diet-and-workout plan that worked for her.

Katherine Jenkins

The Opera beauty lost 21 pounds while on Dancing with the Stars this spring. She told Mail Online, “I like to be curvy so I’m trying not to lose any more, but I do want to be healthy, too. There are so many skimpy costumes to wear — that scares me.”